OpenGL Programming Part I

Graphics

Graphics Lab @ Korea University http://kucg.korea.ac.kr

OpenGL Programming

Part I

Korea Univ.

Computer Graphics Lab.

KUCG

Graphics Lab @ Korea University http://kucg.korea.ac.kr

OpenGL Reference Sites

OpenGL Official Site

http://www.opengl.org/

Khronos Group

http://www.khronos.org/

Nehe Productions

http://nehe.gamedev.net/






















KUCG

Graphics Lab @ Korea University

OpenGL-Related Files

Header File gl.h, glaux.h, glu.h, glut.h

Microsoft SDKs\v6.0A\Include (VS 2008)

or Microsoft SDKs\v7.0A\Include (VS 2010)

Static Library opengl32.lib, glaux.lib, glu32.lib, glut32.lib

Microsoft SDKs\v6.0A\Lib (VS 2008)

or Microsoft SDKs\v7.0A\Lib (VS 2010)

Dynamic Library opengl32.dll, glu32.dll, glut32.dll

C:\WINDOWS\system32

http://kucg.korea.ac.kr

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Project Creation [VS 2008] (1/2)

[File] [New] (Ctrl+Shift+N)

[Project types] [General]

[Templates] [Empty Project]

Enter the project file name


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[Project] [Settings…] (Alt+F7)

[Link] [Input] [Additional Dependencies]

Type ‘opengl32.lib glu32.lib glut32.lib glaux.lib’


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[File] [New] [Project] (Ctrl+Shift+N)

[Visual C++] [Win32] [Win32 Console App]

Enter the project name

[Empty project]


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[Project] [Properties] (Alt+F7)

[Configuration Properties] [Linker] [Input]

[Additional Dependencies]

Type ‘opengl32.lib glu32.lib glut32.lib glaux.lib’


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Example


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OpenGL Primitives

Point

GL_POINTS

Line

GL_LINES

GL_LINE_STRIP

GL_LINE_LOOP

Polygon

GL_POLYGON

GL_TRIANGLES

GL_TRIANGLE_STRIP

GL_TRIANGLE_FAN

GL_QUAD_STRIP


Miscellaneous

Cube

Tetrahedron

Icosahedron

Sphere

Torus

Cone

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Point

GL_POINTS

glBegin(GL_POINTS);

glVertex3f(v1x, v1y, v1z);




glEnd();


v1 v2

v3 v4

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Line (1/3)

GL_LINES

glBegin(GL_LINES);





glEnd();


v1 v2

v3 v4

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Line (2/3)

GL_LINE_STRIP

glBegin(GL_LINE_STRIP);





glEnd();


v1 v2

v3 v4

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Line (3/3)

GL_LINE_LOOP

glBegin(GL_LINE_LOOP);





glEnd();


v1 v2

v3 v4

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Triangle (1/3)

GL_TRIANGLES

glBegin(GL_TRIANGLES);




glEnd();


v1 v3

v2

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Triangle (2/3)

GL_TRIANGLE_STRIP

glBegin(GL_TRIANGLE_STRIP);






glEnd();


v1

v2

v3

v4

v5

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Triangle (3/3)

GL_TRIANGLE_FAN

glBegin(GL_TRIANGLE_FAN);






glEnd();


v1

v2

v3

v4 v5

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Quadrilateral (1/2)

GL_QUADS

glBegin(GL_QUADS);





glEnd();


v1 v4

v3 v2

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Quadrilateral (2/2)

GL_QUAD_STRIP

glBegin(GL_QUAD_STRIP);







glEnd();


v1

v2

v3

v4

v5

v6

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Polygon

GL_POLYGON

glBegin(GL_POLYGON);







glEnd();


v1

v2

v3 v4

v6

v5

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Miscellaneous (1/3)

Cube

void glutSolidCube(GLdouble size)

void glutWireCube(GLdouble size)

Tetrahedron

void glutSolidTetrahedron(void)

void glutWireTetrahedron(void)

Icosahedron

void glutSolidIcosahedron(void)

void glutWireIcosahedron(void)


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Miscellaneous (2/3)

Sphere

void glutSolidSphere(GLdouble radius, GLint slices, GLint stacks)

void glutWireSphere(GLdouble radius, GLint slices, GLint stacks)

Torus

void glutSolidTorus(GLdouble innerRadius, GLdouble

outerRadius, GLint nsides, GLint rings)

void glutWireTorus(GLdouble innerRadius, GLdouble outerRadius,

GLint nsides, GLint rings)


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Miscellaneous (3/3)

Cone

void glutSolidCone(GLdouble base_radius, GLdouble height,

GLint slices, GLint stacks)

void glutWireCone(GLdouble base_radius, GLdouble height, GLint

slices, GLint stacks)

Teapot

void glutSolidTeapot(GLdouble size)

void glutWireTeapot(GLdouble size)


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Teapot Example


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Basic Functions (1/2)

glPointSize(GLfloat size)

glGetFloatv(GL_POINT_SIZE_RANGE)

Returns the range of the point size that the hardware supports

glLineWidth(GLfloat width)

glGetFloatv(GL_LINE_WIDTH_RANGE)

Returns the range of the line width that the hardware supports


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Point Example


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Basic Functions (2/2)

glShadeModel(mode)

Sets the polygon filling method

mode

GL_FLAT

By only one color

GL_SMOOTH

By the weighted averaging the colors of member

vertices (gradation)

Default value


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Line Example


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Triangle Example


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Rectangle Example : Revisited


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‘Single vs. Double Buffering’

glFlush() vs. glutSwapBuffers()

Single Buffering (GLUT_SINGLE, Default)

Double Buffering (GLUT_DOUBLE)

cf.) triple buffering

Graphic Processor

Frame Buffer

Video Controller

Display Device

Graphic Processor

Front Buffer

Video Controller

Display Device

Back Buffer

Slow Very Fast


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Single Buffering vs. Double Buffering :

Assumption & Environment

Assumption

Time to write a frame (graphic processor, GPU)

10ms

Time to read a frame (video controller, CTRL)

3ms

No delay for switching read/write modes

Can’t read & write the frame buffer at the same time

Mutual exclusion

Compare the time to display 3 frames


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Single Buffering

Step 1 (0ms) : 10ms

GPU Write frame #1 into the frame

buffer

Step 2 (10ms) : 3ms

CTRL Read frame #1 from the

frame buffer

Shoot frame #1 to the display

Step 3 (13ms) : 10ms

GPU Write frame #2 into the frame

buffer

Step 4 (23ms) : 3ms CTRL

Read frame #2 from the frame buffer


Step 5 (26ms) : 10ms GPU

Write frame #3 into the frame buffer


Read frame #3 from the frame buffer


Complete (39ms) Avg. 13ms/frame


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Double Buffering


Write frame #1 into the front buffer


Read frame #1 from the front buffer


GPU Write frame #2 (30%) into the

back buffer


Write frame #2 (70%) into the back buffer


Read frame #2 from the back buffer


GPU Write frame #3 (30%) into the

back buffer


Write frame #3 into the back buffer


Read frame #3 from the back buffer


Complete (33ms) Avg. 11ms/frame


Documents

OpenGL Programming Part I